Pennatulaceans are a morphologically diverse group with an estimated 200 or more valid species, displaying worldwide geographic and bathymetric distributions from intertidal areas to over 6100 m in depth (Williams, Reference Williams2011). Pennatulaceans have a specialized morphology and, unlike other octocorals, they are formed by a single large primary polyp, also known as the oozooid. The primary polyp is penetrated into soft sediment by a proximal muscular peduncle (Williams, Reference Williams2011). Although a few species are capable of inhabiting rocky surfaces, generally, they colonize intertidal sand or mud flats, sandy areas on or near coral reefs, shallow water areas of mud or rubble, continental shelves and slopes, rocky outcrops between approximately 600 and 2000 m in depth, abyssal plains and hadal trenches (Williams, Reference Williams2011). Pennatulaceans form one of the most complex biogenic habitats of the sea, providing various microhabitats that serve as shelter, feeding, foraging and spawning sites to other species (Murillo et al., Reference Murillo, Duran Munoz, Altuna and Serrano2011; Baillon et al., Reference Baillon, Hamel, Wareham and Mercier2012). They are well known and have stable systematics compared to other octocoral groups (Altuna et al., Reference Altuna, Aguirrezabalaga and Martinez2008). Williams (Reference Williams1989) paid particular taxonomic attention to the genus Cavernularia and Williams (Reference Williams1995) has given a diagnosis of this genus. Later, Lopez-Gonzelez et al. (Reference López-González, Gili and Williams2000) provided a revised key to the world species of Cavernularia. Cavernularia pusilla (Philippi, Reference Philippi1835) is considered the only valid species of the genus present in the Mediterranean Sea (Williams, Reference Williams1989; Lopez-Gonzalez et al., Reference López-González, Gili and Williams2000).

In August 2014, twelve specimens of C. pusilla were collected with R/V Alemdar in two locations (A: 40°24′23.5800″N 26°42′24.0600″E, depth 73 m, one specimen; B: 40°57′38.5800″N 27°31′29.5800″E, depth 22 m, 11 specimens) on the Marmara Sea coast (Figure 1). The samples were collected on sandy and clay-silt mixture substrate using a Van Veen grab in both locations. The bottom water temperature and salinity amounted to 17.4°C and 38.5 psu, respectively in location A, and 19.8°C and 29.4 psu in location B. The specimens were identified using Williams (Reference Williams1989) and Lopez-Gonzelez et al. (Reference López-González, Gili and Williams2000) (Figure 2). The specimens are preserved at the Fisheries Faculty Museum, Sinop University, Sinop (SNUFF-ANT/2014-36). They are elongate clavate, 1.5–3.7 cm in length and have a long internal axis that does not reach the proximal end of the colony. Peduncle length is approximately 60% of colony length. Rachis distinguishably expanded distally. Autozooids few (usually <30), partially retracted into rachis. They are not arranged in longitudinal rows and absent from distal terminus of rachis. Siphonozooids numerous and crowded between the autozooids. Autozooid sclerites present in base, not observed in tentacles. Rachis surface contains slender rods but peduncle surface contains irregular rods. Peduncle interior sclerites are minute ovals.

Fig. 1.

Map of the Sea of Marmara showing the sampling locations. A: Tekirdağ; B: Dardenelles.

Fig. 2.

Cavernularia pusilla (Philippi, Reference Philippi1835). Scale bar: 1 cm.

The most representative accompanying macrofauna was Amphipholis sp., Bittium reticulatum (da Costa, 1778), Loripes lucinalis (Lamarck, 1818), Microdeutopus versiculatus (Bate, 1856), Iphinoe elisae (Băcescu, 1950), Apocorophium acutum (Chevreux, 1908), Aonides paucibranchiata Southern, 1914, Eunice vittata (Delle Chiaje, 1828), Paradoneis lyra (Southern, 1914), Sigambra tentaculata (Treadwell, 1941) and Ampelisca pseudosarsi (Bellan-Santini & Kaim-Malka, 1977). Altuna et al. (Reference Altuna, Aguirrezabalaga and Martinez2008) stated that C. pusilla is a typical neritic species, showing similar bathymetric distribution patterns within a wide geographical scope, from 44°N to 12°S. The deepest record for this species was taken from 200 m depth off Catalonia (Gili & Pagès, Reference Gili and Pagès1987), and the shallowest, from 14 m depth off Algeciras Bay (Lopez-Gonzalez, Reference López-González1993).

Cavernularia pusilla was recorded from the Bay of Biscay to Senegal (Williams, Reference Williams1989; Altuna et al., Reference Altuna, Aguirrezabalaga and Martinez2008), the Western Mediterranean (Kükenthal & Broch, Reference Kükenthal and Broch1911; Gili & Pagès, Reference Gili and Pagès1987). Vafidis et al. (Reference Vafidis, Koukouras and Voultsiadou-Koukoura1994) reported it for the first time from the Eastern Mediterranean (Aegean Sea). After that, Abdelsalam (Reference Abdelsalam2014) reported it from Egyptian waters of the Mediterranean. The latest list published by Çınar et al. (Reference Çınar, Yokeş, Açık and Bakır2014) presents the actual status of species diversity of Anthozoa from the Turkish coast and reports 75 species in total. According to the available literature, C. pusilla is considered an Atlanto-Mediterranean species and the present record of C. pusilla is the first from Turkish seas, which represents an addition to the biodiversity of the Turkish fauna.